Luminescence spectroscopic measurements of ZnSe/GaAs(100) hetero-junctions that had been grown by molecular beam epitaxy revealed the formation of deep levels near to buried interfaces during thermal annealing. A pronounced emission at 1.9 to 2.0eV appeared at temperatures of between 300 and 400C, depending upon the ZnSe growth conditions, with a constant activation energy of 1.10eV. The use of X-ray photo-emission spectroscopy revealed a correlation between this deep level and the atomic diffusion of Ga and Zn across the hetero-interface. The use of Zn-rich ZnSe growth conditions markedly reduced this emission, and emphasized the importance of the local interface composition for thermal stability.

A.D.Raisanen, L.J.Brillson, L.Vanzetti, A.Bonanni, A.Franciosi: Applied Physics Letters, 1995, 66[24], 3301-4